And now for the fun part! PENTODE is an exciting new way to learn or brush up your Morse code. When you click 
(or press Enter) PENTODE starts sending you Morse characters. Your job is to get rid of them by placing them in the central panel. Two characters placed side by side blow up and eliminate themselves. This is called a DIODE. You can keep the screen clear just by making diodes but if you want a high score you need to make TRIODES, TETRODES and PENTODES -- especially PENTODES
You make a TRIODE when you place two similar characters on a diagonal and then place a third character in the angle so that all three explode at once, and so forth as shown below.
Your score increases very fast as you progress from Diodes to Pentodes. It is then further increased by the multiplier shown in the top panel. The number of tiles here show how far 'behind' you are. A good Morse decoder can keep several characters in his head and not lose track. The multipliers provide a reward for this type of 'stacking' -- up to a point. The multipliers go:
After that you lose! To make the highest score possible make as many Pentodes as you can and always wait until 
appears before entering the last tile.
There are two variations of PENTODE . In REGULAR PENTODE all the characters you place disappear, while in the more advanced CHALLENGE PENTODE the final character you place remains. This makes it harder to clear the screen and just making diodes doesn't reduce the number of characters on the screen at all. You can select CHALLENGE PENTODE and other game options from the Pentode Options Dialog Box
People who fancy themselves as gamers might want to start with CHALLENGE PENTODE
If you are just learning Morse code, you will want to play at the TECHNICIAN level. After 10 rounds (if you survive), you advance to the TECH. PLUS level and then through the GENERAL and EXTRA levels to the VE level. At each level, and as you progress through the rounds, the Morse transmission rate increases. If you don't know Morse code yet and just want to play the game, we have provided the option of having spoken numbers instead of Morse code. Again, all these options may be set from the Pentode Options Dialog Box which can be reached either by clicking 
or by selecting Game Options from the Preferences Menu. (For those who don't know, this is the symbol for a Pentode).